Animals > Animal Diseases > Bovine Spongiform Encephalopathy Bovine Spongiform Encephalopathy (BSE)Main Page - Animal Disease Information | Main Page - BSE What is BSE?BSE or "Mad Cow Disease" is a progressive, fatal disease of the nervous system of cattle. It is what is known as a transmissible spongiform encephalopathy (TSE). Other TSEs include scrapie in sheep, chronic wasting disease in deer and elk, and Creutzfeldt-Jakob disease in humans. Although the exact cause of BSE is unknown, it is associated with the presence of an abnormal protein called a prion. There is no treatment or vaccine currently available for the disease. BSE in CanadaIn 1993 BSE was found in a beef cow that had been imported from Britain in 1987. The animal was destroyed and additional measures were taken immediately by the federal government to deal with any risk that Canadian cattle might have been affected. Through Canadas BSE surveillance program there have been 3 cases of BSE found in Canada since 2003. The first case of BSE was reported May 20, 2003. The animal was condemned at slaughter and no meat from the carcass entered the human food system. The CFIA responded with a comprehensive investigation that tested some 2,000 animals. All test results were negative for BSE. The second and third cases were confirmed on January 2 and 11, 2005, respectively. Neither of these animals entered the human food or animal feed systems. Investigations into these 2 cases are complete and all of the animals depopulated through this investigation tested negative for BSE. BSE has been a reportable disease in Canada since 1990. Symptoms/Signs of BSEBSE is an unusual disease in that the time between an animals exposure to the disease and the onset of clinical signs normally ranges from four to five years. Animals with BSE may show a number of different symptoms including nervous or aggressive behavior, abnormal posture, lack of co-ordination or difficulty in rising from a lying position, decreased milk production, and weight loss despite an increased appetite. These symptoms may last for a period of two to six months before the animal dies. Transmission of BSEScientists believe that the spread of this disease in cattle in Great Britain was caused by feeding protein products made from infected cattle or sheep. This occurred in the late 1970s and early 1980s. It was then magnified by the practice of feeding rendered material from slaughtered cattle to other cattle. The protein that is linked to BSE is resistant to normal inactivation procedures such as heat, which means that it may not be completely destroyed in the rendering process and could remain active in rendered material. In 1988, Great Britain banned the use of this rendered material in animal feeds, thus removing potentially contaminated material from the food chain. As a result, since the winter of 1992-93, the number of BSE cases reported in Great Britain has been progressively dropping. In addition, other possible methods of transmission are still being scientifically investigated. Diagnosis of BSEThere is no test to diagnose BSE in live animals, although a tentative diagnosis may be made based on clinical signs. Diagnosis can only be confirmed by microscopic examination of the animals brain after its death. How Does Canada protect food safety and animal health from BSE?Canada, as well as many other countries, has taken precautions to prevent the introduction and spread of BSE. These measures include the following:
Canada is continually assessing international scientific information as it becomes available and modifying policies as required, based on new information. |
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